The general aim of this work is to study the development and control of carbohydrate and lipid metabolism during the perinatal period in guiena pig liver. Specifically this work aims at providing a new model for the study of neonatal hypoglycemia and related metabolic disorders associated with development. This investigation will center around three major areas: 1) evaluation of the capacity of fetal and newborn guinea pig liver to synthesize glucose; 2) assessment of the intrahepatic oxidation-reduction states in fetal and neonatal guinea pig liver and of the effect of anoxia on neonatal gluconeogenesis; 3) a study of the developmental interrelationship between gluconeogenesis and lipid metabolism and hormonal regulation of these processes in the perinatal period. The isolated hepatocyte system will be used to measure gluconeogenesis, ketogenesis, and lipogenesis. By employing specific inhibitors of these pathways, this system will be used to decipher functionally in these pathways during development. The freeze-clamp technique will be used to assess the level of metabolic intermediates in vivo. Bibliographic references: Patel M. S. and Arinze I.J. (1975) Phenylketonuria: Metabolic alterations induced by phenylpyruvate and phenylalanine Am J. Clin. Nutr. 28, 183-188.